Various ecological and biological aspects of the wood duck (Aix sponsa)were investigated in the elm-ash-maple (Ulmus-Fraxinus- Acer) bottomland timber impoundments at Montezuma National Wildlife Refuge in central New York. Major areas of research included (a) a description of the forest stand with special reference to the ecological impact of seasonal impoundment, (b) the pattern of occurrence and use of natural nest cavities by wood ducks, (c) the nesting response of wood ducks to nest boxes, (d) an investigation of dump nesting, (e) mark-recapture estimates of annual duckling production, (f) a study of vernal pool invertebrates, and (g) a study of brood usage and survival. Spring flooded green timber was found to produce ideal breeding habitat for wood ducks in providing ample acceptable nest cavities (1.60 per acre)and an abundance of early spring (vernal pool) invertebrate food resources, including fairy shrimp (Chirocephalopsis bundyi), cladocerans (Daphnia pulex), mosquito lar.